Aryeh3, think about it. When you claim that 6,000,000 Jews have been lost to assimilation, why did that happen? Why did the Reform movement come about in the first place? Maybe because we made yiddishkeit so unpalatable to the masses by insisting on things that are not even halacha, that they all became turned off.
There were fights over speaking any language other than yiddish, studying secular subjects, choirs in shul, dressing in up to date clothing, as opposed to long black coats, etc. All these things have nothing to do with halacha (see Reb Moshe that American garments are not chukos akum). Because no flexibility was shown to many Jews, they said who needs this, and took off for greener pastures. The gemara says l’olam yehei smol docheh vyimin mekarev.